The exemplary embodiment relates to lubricant additives and in particular to ionic borate compounds useful in lubricating compositions.
Thermal and mechanical stresses on lubricants, such as engine and driveline oils, tend to increase the tendency towards formation of deposits on the lubricated components, such as internal combustion engines and driveline components. This can negatively impact the performance of the lubricated components through reduction in engine efficiency or overall life-expectancy. Such lubricants generally incorporate, in addition to a base oil, a number of additives, including friction modifiers, antiwear agents, antioxidants, dispersants, and detergents, that are used to protect lubricated components from wear, oxidation, soot deposits, corrosion, acid build up, and the like, and to improve water tolerance and compatibility of formulation components.
Dispersants are used for dispersing impurities such as wear particles, soot and other contaminants. Amine-based dispersants, such as polyamine succinimides, have been widely used. These dispersants often have basic functionality which can help to neutralize acidic contaminants. However, they have a tendency to reduce corrosion protection and seals compatibility.
Salicylate and catecholate additives have been used to provide desirable performance attributes to lubricant formulations, including cleanliness, antioxidancy, and dispersancy.
U.S. Pat. Nos. 7,423,000 and 7,582,126 disclose compositions containing catechol compounds, such as tertiary alkyl substituted catechols.
Borate-based additives are also known to provide desirable attributes, including corrosion resistance, antioxidancy, water tolerance and compatibility.
U.S. Pat. No. 5,102,569 discloses borated alkyl aromatic polyols for use in lubricating oil formulations to reduce oxidation, wear, and deposits in internal combustion engines. U.S. Pat. Nos. 2,795,548 and 5,284,594 disclose lubricating oil compositions containing a borated alkyl catechol. U.S. Pub. No. 20080171677 discloses a lubricating oil composition which includes a borated hydroxyl ester, such as borated glycerol monooleate.
The exemplary ionic borate compounds provide lubricating compositions with good dispersion and/or detergent properties while reducing and/or limiting detrimental effects commonly associated with basic amine additive containing lubricants, such as poor seal compatibility, deposit formation, and reduced corrosion protection.